[Hank70SS]

You mentioned the interior then engine bay, so it sounds like you're doing everything.

There are 2 main harnesses in the engine bay.

The engine harness has wiring for starter, ignition coil, wipers, blower motor, TCS, temp and oil senders. No grounds with this harness as the engine is the ground and it's connected right to the negative battery post. The wiper relay is grounded to the firewall by the mounting screw.

The light or forward harness has wiring for all forward lights, horns, voltage reg, alt, temp and brake warning lights. This harness has grounds that attach to core support on each side near headlights.

The chassis is grounded through the pigtail off the negative battery cable attached to the passenger side front fender.

There are of course additional harnesses for options like cruise control and AC.

As for grounds in the engine bay what I mentioned is about it. Now if the car came with a radio then you'll have 2 braided straps off the valve covers to the firewall and one down lower on the passenger side of the engine. If it was an FM radio then I believe there was a 4th ground strap. These are not circuit grounds, they are not meant to carry current, only meant to help suppress ignition electrical noise. I would not add these until the car is finished and running properly. Then you know all the circuit grounds are good and the radio ground straps are not acting as circuit grounds.

Then there's the dash harness, the other main harness in the car. It's pretty obvious what it does, it has the fuse panel that connects to the bulkhead connector on the firewall, engine and light harnesses.

The headlight switch has a metal ring around it that is part of the ground circuit. It has a wire that attaches to the metal bracket for the wiper switch. The wiper switch bracket get's bolted to the metal dash frame. There should be 3 (?) ground wires in the dash harness, one goes to parking brake assembly. One to the metal bracket that goes to wiper switch, connects where the bracket is bolted to the metal dash frame. One to the back of the gauge cluster. The circuit board is grounded by the wire just mentioned and 5 screws that hold it to the gauge cluster.

Again there are additional harnesses, like console extension, rear light harness, actually 2 harnesses on a 70, and others. If you're replacing all harnesses you're talking major bucks. The dash harness is the most expensive and runs close to $500.

EDIT: I'm sure we can find some pic's to help out. If not my dash is coming out soon so I can restore it, I can take some pics then.